JPS5831420A - Integrated power supply device - Google Patents

Abstract

PURPOSE:To operate up to low power supply voltage by combining a constant- voltage means, a constant-current supplying means and a transistor to obtain a standard output. CONSTITUTION:An integrated power supply device is provided with a constant- voltage circuit 12 having a negative temperature factor which is approximately constant in spite of the change of bias current, a constant-current source 13 supplying bias current to the constant-voltage circuit 12, a transistor (TR)1 in which the terminal voltage of the constant-voltage circuit 12 is applied to the base, the emitter is connected to an electric power supplying line 7b through a register 15 and a negative temperature factor is given to the collector current, a TR1 to which forward bias current dependent on the collector current of the TR14 is supplied, and a TR2 in which the terminal voltage of the TR1 is applied to the base and the emitter is connected to the electric power supplying line 7b through the register 5. Standard output voltage or standard output current is taken out from the collector or emitter of the TR2.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an integrated power supply device that occupies a small area and can operate up to a low power supply voltage, including (1) a reference voltage source or reference current source having an arbitrary temperature coefficient including zero; .

(11) A reference voltage source or reference current source whose operation and characteristics are guaranteed under extremely low power supply voltages.

0+++ Reference voltage source or reference current source with a very wide output voltage or output current range under zero temperature coefficient.

(IV) A reference voltage source capable of generating a reference voltage of zero temperature and coefficient with a smaller chip area than known bandgap reference voltage sources.

It is effective in realizing this.

Conventional examples include RJ, WIDLAR” New De
velopments in IC Voltage Re
gulators” IEEE ICIJRRAL
OF Sot, ID-8TATE CIRCUITS
, Voj, 5C-6, AI, PP2-7 Feb,
The bandgap reference voltage source circuit described in 1971 is shown in FIG.

Because it can obtain a low-voltage output voltage with a zero temperature coefficient with an extremely simple circuit configuration, it is often used inside integrated circuits that need to operate under a low power supply voltage, such as portable devices that use dry batteries. ! There is.

In FIG. 1, the emitter current density of the transistor is 11. The emitter current density of transistor 2 is I2. Assuming that the voltage between the base and emitter of the transistor 30 is V, the resistance values of the resistors 4 and 5 are R4, E3, and R6, respectively, and the DC current amplification factor of each transistor is sufficiently large, the voltage between the collector and emitter of the transistor 3 is ``CH2 is given by the following formula.

Here, k is Boltzmann's constant, k-1, 38X10-23joatle/, K and q
is the electron charge q -1,602X10-0-19couloFurthermore,
T is the absolute temperature (0K).・Also, the temperature coefficient of the output voltage cE3 expressed by equation 0) is given by the following equation.

As is well known, avBE3/aT is about -2mV/
℃, so now, if we take 11/12-10 as an example, then R4/R
When 5=-1o, Equation G3) becomes 0.

Further, at this time, vcE3 is approximately 12V from equation (1).

That is, in FIG. 1, when the emitter area of transistor 2 is set to 10 times the emitter area of transistor 1, and the resistance value of resistor 4 is set to 10 times the resistance value of resistor 5, the The temperature coefficient of the output voltage appearing between the collector and emitter is zero.

Similarly, if you change the values of J and /J2 and calculate,
If J1/J2-2 is set to 2, R4/R6 is 33.
．． 5, the temperature coefficient becomes zero, and 1. ．． 4. When set to -4, the temperature coefficient becomes zero when R4/R5 is 16.7, and when set to J1/J2-6, R4/R
When 5 is 13.0, there is a zero temperature coefficient.

Note that the output voltage at zero temperature coefficient is approximately 1.2 in both cases.
It is v.

By the way, as the name suggests, the bandgap constant voltage source circuit shown in Fig. 1 has a zero temperature coefficient only when the output voltage is a voltage corresponding to the silicon bandgap. If a reference voltage larger than 1.2V is required, or if a reference voltage smaller than 1.2V is required, it is necessary to multiply or divide the output voltage using a current mirror circuit, etc. was there.

In addition, since the constant current source 6 in Fig. 1 generally uses a current mirror circuit, a minimum voltage of about 0, sV is required, so if the output voltage of the battery 7 is 2V or less, satisfactory characteristics can be expected. There was a problem that I couldn't do it.

Furthermore, as shown in the calculation example, in order to obtain a zero temperature coefficient, the emitter area ratio of transistor 2 and transistor 1 and the resistance ratio of resistor 4 and resistor 5 must be set to a high ratio. The area required and tracking of temperature characteristics became a problem.

For example, in the circuit shown in FIG. Area and transistor 3
Even if the area of
Two resistors are required, and since the resistance value of the resistor 8 needs to be approximately the same as the resistance value of the resistor 4, an area 21 times that of the unit resistor (resistance 5) is required.

Furthermore, several transistors and resistors are required to configure the constant current source 6, so although the bandgap constant voltage source shown in Figure 1 has a simple circuit configuration, it requires an integrated circuit to actually configure it. The circuit requires a lot of real estate on the chip and therefore thermal tracking (both physical and
It is necessary to maintain 1/I2-10 and R4/R6-1o,
be. ) was difficult to solve.

The present invention solves the above problems.

FIG. 2 shows a circuit connection diagram of a reference voltage source circuit according to an embodiment of the present invention, in which the same parts as in FIG. 1 are designated by the same reference numerals.

In FIG. 2, a transistor 9 and the transistor 9
A constant current source 13 supplies a bias current to a constant voltage circuit 12 configured by a resistor 1o connected between the base and collector of the transistor and a resistor 11 connected between the base and emitter of the transistor 14. The output voltage of the constant voltage circuit 12 is applied thereto, and a resistor 15 is connected between the emitter of the transistor 14 and the negative power supply line 7b.

On the other hand, the positive side feed line 7a and the negative side feed line 7b
A resistor 17 is connected between the base and emitter of the transistor 1 via a constant current source 16, and the collector of the transistor 1 is directly connected to the base.A transistor 2 is connected to the base (collector) side of the transistor 10.
The base of the transistor 2 is connected to the base of the transistor 18, the emitter of the transistor 2 is connected to the negative power supply line 7b via the resistor 5, the collector of the transistor 2 is connected to the collector and base of the transistor 18, and the transistor 2 constituting the constant current source 13 is connected to the base of the transistor 18. 19. The emitter of the transistor 18 is connected to the base of the output transistor 20, and the emitter of the transistor 18 is connected to the resistor 21.
It is connected to the plus side feed line 7a via.
- Also, the emitters of the transistors 19 and 20 are connected to the positive power supply line 7 via resistors 22 and 23, respectively.
The collector of the transistor 20 is connected to the negative power supply line 7b via a resistor 24.

Furthermore, the collector of the transistor 14 is connected to the collector and base of the transistor 25 and the base of the transistor 260, and the emitters of the transistors 25 and 26 are connected to the positive power supply line 7a through resistors 27 and 28, respectively.

Now, in the circuit shown in diagram R2, transistors 1 and 2
The blade pressure between the base and emitter of is vBEl and vB, respectively.
E2, and the resistance values of resistors 5 and 17 (7) are R6, respectively.
・, R1□, and the collector current of the transistor 26 is 26, then the collector current I of the transistor 2 is
2 is given by the following equation.

Here, to simplify the explanation, suppose that the resistance values of the resistors 21 and 230 are the same, and that the transistors 18 and 2o are also the same size, then the output voltage vx appearing across the resistor 24 is... (6) Note that in equation (5), R24 is the resistance value of the resistor 24.

By the way, if the emitter areas of transistors 1 and 2 are Ae and NAe, respectively, then (67, (
In formula 7), Io is the reverse saturation current per unit area.

Above (5)? From equations (6) and (7),...
...(8) □ Meanwhile, between the base and emitter of transistors 9 and 14! The pressures are VBE9 and vBE14, respectively, and the resistance values of the resistors 10° and 11.15 are R1°, R11, and R11, respectively.
Assuming R1°, the collector current 114 of the transistor 14 is as follows.

15 By setting the resistance value of the resistor 27 and the resistance value of the resistor 28 to be equal, the formula 14''26 is established.

Also, assuming that vBE9=VBE14 approximately holds true, then from the above equation (10), in the region where the temperature coefficient of the output voltage vx is quite small, the temperature coefficient of the current generator depends on the temperature coefficient of the resistor 6. .

In other words, assuming that the resistance on the IC chip has the same temperature coefficient on the pan, the value of the logarithmic term in equation (11) has the same temperature coefficient as the temperature coefficient of vBE9, and the value is approximately -3000ppm.

Further, since the temperature coefficient of kT/q is approximately +3000 ppm, when the absolute value of the logarithmic term is around 2.7, the temperature coefficient of the first term of equation (11) becomes zero.

To satisfy this condition, the emitter current density of transistor 1 must be set to 2.7 of the emitter current density of transistor 2.
In this case, the resistor 17 is unnecessary (R1□
-0).

Furthermore, when the absolute value of the logarithmic term is greater than 2.7, the temperature coefficient of the first term in equation (11) will be a positive value, so the resistance value of the resistor 17 can be appropriately set. , (1
1) Output voltage V given by formula! The temperature coefficient of can be made zero.

By the way, when actually calculating the value of each resistor, when the emitter area ratio of transistor 1 and transistor 2 is set to 1 (N-1), the resistance value of resistor 6 is 260Ω, and the resistance value of resistor 10 is 21.23 .27.The resistance value of 28 is 1Ω, the resistance value of resistor 11 is 10Ω, and the resistance value of resistor 15 is 260Ω.
If the resistance value of the resistor 22 is set to 3000, and the resistance value of the resistor 24 is set to 2.6Ω, the value of the output voltage v8 becomes 0.26V, and the temperature coefficient also becomes zero.

Using this constant to calculate the area occupied by the circuit in Figure 2, we find that the emitter area of each transistor can all be the same, so the number of transistors is 9, and all resistances less than 1Ω are 1, the number of unit resistances is 22, with Ω being the standard.

Therefore, although the number of elements is increased in the circuit of FIG. 2 compared to the circuit of FIG. 1, the area occupied is much smaller.

(The circuit in Figure 1 requires 12 unit transistors even excluding the constant current source 6.) In addition, in the circuit in Figure 2, as is clear from the circuit configuration, the power supply voltage is 1. It works well even when the voltage is around .6v.

Furthermore, from equation (11), by appropriately setting the resistance ratio of resistor 6 and resistor 24, it is possible to arbitrarily select the output voltage
．． It can also be seen that by appropriately setting the resistance value of 15.17, a minute output voltage with an arbitrary temperature coefficient can be obtained.

In addition, the process of deriving equation (11) vBE9'''BE14
However, in the circuit shown in FIG. 2, the emitter current of transistor 9 has a positive temperature coefficient in a state where an output voltage with zero temperature coefficient is obtained (temperature coefficient of resistor 10. is positive), whereas the temperature coefficient of the emitter current of transistor 14 is negative, so in reality, considering the temperature characteristics, vBE9''-vB
E14 does not hold.

However, there is no doubt that the collector current of the transistor 14 has a negative temperature coefficient.
It was set as m. ) can be absorbed by reducing the emitter current density of the transistor 1, increasing the resistance value of the resistor 17, or making the output current of the current source 13 have a negative temperature coefficient.

Note that the integrated power supply device of the present invention is not limited to the embodiment shown in FIG. 2; for example, the integrated power supply device shown in FIG.
If the output current is taken out from the collector of transistor 2o, it becomes a reference current source, and transistor 2o
Alternatively, if the output is compared from the emitter side of the transistor 18, the transistor 2o and the resistor 2
3.24 is no longer necessary.

Further, the constant voltage circuit 12 may be a circuit in which diodes are connected in series, or only the resistor 1o may be replaced with a diode (PN
It can also be replaced with (joining).

That is, the integrated power supply device of the present invention includes: a constant voltage means (corresponding to the constant voltage circuit 12) whose terminal voltage is substantially constant with respect to changes in bias current and has a negative temperature coefficient; The terminal voltage of the constant voltage means is applied to the current supply means (corresponding to the constant current source 13) and the base, and the emitter is connected to one electric line through a resistor, and the collector current is negative. A first transistor (corresponding to transistor 14) having a temperature coefficient, a PN junction (corresponding to transistor 1) to which a forward bias current depending on the collector current of the first transistor is supplied, and a base of the PN junction. A terminal voltage of 2 is applied, and the emitter is provided with an M2 transistor (corresponding to transistor 2) connected to one of the feed lines via a resistor, and a reference output voltage or reference output is applied from the collector or emitter of the second transistor It is configured to extract current, and has great effects compared to conventional bandgap reference voltage source circuits, such as being able to operate at lower power supply voltages and occupying less space. It is something.

[Brief explanation of the drawing]

FIG. 1 is a circuit connection diagram showing a conventional example, and FIG. 2 is a circuit connection diagram of two embodiments of the present invention. 1.2,14...me transistor, 7...
Power supply, 7a...Positive feed line, 7b...
... Maina side power supply line, 12 ... Constant voltage circuit, 13 ... Constant current source Name of agent: Patent attorney Toshio Nakao and one other person wh
l figure

Claims (1)

[Claims] (1) a constant voltage means whose terminal voltage is approximately constant with respect to changes in bias current and has a negative temperature coefficient; a current supply means for supplying a bias current to the constant voltage means; a first transistor to which a terminal voltage is applied, whose emitter is connected to one of the feed lines via a resistor, and whose maleft terminal current has a negative temperature coefficient; and a forward bias depending on the collector current of the first transistor. a PN junction to which a current is supplied, a second transistor to which a terminal voltage of the PN junction is applied to the pace, and an emitter connected to one power supply line via a resistor;
An integrated power supply device characterized in that the reference output voltage or the reference output current is extracted from the collector or emitter of the second transistor. @) In the description of claim O), the constant voltage means is constituted by a third transistor in which a resistor is connected between the pace collector and between the pace emitter, and the PN junction is constituted by a fourth transistor. The transistor base of
What is claimed is: 1. An integrated power supply device comprising a j-s emitter junction, and wherein the emitter current density of the fourth transistor is set to be higher than the emitter current density of the second transistor.